Trait diesel::serialize::ToSql

pub trait ToSql<A, DB: Backend>: Debug {
    // Required method
    fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, DB>) -> Result;
}

Serializes a single value to be sent to the database.

The output is sent as a bind parameter, and the data must be written in the expected format for the given backend.

When possible, implementations of this trait should prefer using an existing implementation, rather than writing to out directly. (For example, if you are implementing this for an enum, which is represented as an integer in the database, you should use i32::to_sql(x, out) instead of writing to out yourself.)

Any types which implement this trait should also #[derive(AsExpression)].

Backend specific details

• For PostgreSQL, the bytes will be sent using the binary protocol, not text.
• For SQLite, all implementations should be written in terms of an existing ToSql implementation.
• For MySQL, the expected bytes will depend on the return value of type_metadata for the given SQL type. See MysqlType for details.
• For third party backends, consult that backend’s documentation.

Examples

Most implementations of this trait will be defined in terms of an existing implementation.

#[repr(i32)]
#[derive(Debug, Clone, Copy, AsExpression)]
#[diesel(sql_type = Integer)]
pub enum MyEnum {
    A = 1,
    B = 2,
}

impl<DB> ToSql<Integer, DB> for MyEnum
where
    DB: Backend,
    i32: ToSql<Integer, DB>,
{
    fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, DB>) -> serialize::Result {
        match self {
            MyEnum::A => 1.to_sql(out),
            MyEnum::B => 2.to_sql(out),
        }
    }
}

Using temporary values as part of the ToSql implementation requires additional work.

Backends using RawBytesBindCollector as BindCollector copy the serialized values as part of Write implementation. This includes the Mysql and the Pg backend provided by diesel. This means existing ToSql implementations can be used even with temporary values. For these it is required to call Output::reborrow to shorten the lifetime of the Output type correspondingly.

#[repr(i32)]
#[derive(Debug, Clone, Copy, AsExpression)]
#[diesel(sql_type = Integer)]
pub enum MyEnum {
    A = 1,
    B = 2,
}

impl ToSql<Integer, diesel::pg::Pg> for MyEnum
where
    i32: ToSql<Integer, diesel::pg::Pg>,
{
    fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, diesel::pg::Pg>) -> serialize::Result {
        let v = *self as i32;
        <i32 as ToSql<Integer, diesel::pg::Pg>>::to_sql(&v, &mut out.reborrow())
    }
}

For any other backend the Output::set_value method provides a way to set the output value directly. Checkout the documentation of the corresponding BindCollector::Buffer type for provided From<T> implementations for a list of accepted types. For the Sqlite backend see SqliteBindValue.

#[repr(i32)]
#[derive(Debug, Clone, Copy, AsExpression)]
#[diesel(sql_type = Integer)]
pub enum MyEnum {
    A = 1,
    B = 2,
}

impl ToSql<Integer, diesel::sqlite::Sqlite> for MyEnum
where
    i32: ToSql<Integer, diesel::sqlite::Sqlite>,
{
    fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, diesel::sqlite::Sqlite>) -> serialize::Result {
        out.set_value(*self as i32);
        Ok(IsNull::No)
    }
}

Required Methods

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, DB>) -> Result

See the trait documentation.

Implementations on Foreign Types

impl ToSql<BigInt, Pg> for i64

Available on crate feature postgres_backend only.

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> Result

impl ToSql<Bool, Pg> for bool

Available on crate feature postgres_backend only.

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> Result

impl ToSql<CChar, Pg> for u8

Available on crate feature postgres_backend only.

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> Result

impl ToSql<Double, Pg> for f64

Available on crate feature postgres_backend only.

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> Result

impl ToSql<Float, Pg> for f32

Available on crate feature postgres_backend only.

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> Result

impl ToSql<Integer, Pg> for i32

Available on crate feature postgres_backend only.

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> Result

impl ToSql<MacAddr, Pg> for [u8; 6]

Available on crate feature postgres_backend only.

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> Result

impl ToSql<Oid, Pg> for u32

Available on crate feature postgres_backend only.

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> Result

impl ToSql<SmallInt, Pg> for i16

Available on crate feature postgres_backend only.

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> Result

impl ToSql<Timestamp, Pg> for SystemTime

Available on crate feature postgres_backend only.

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> Result

impl<'a, A, T, DB> ToSql<A, DB> for &'a Twhere DB: Backend, T: ToSql<A, DB> + ?Sized,

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, DB>) -> Result

impl<'a, T, ST, DB> ToSql<ST, DB> for Cow<'a, T>where T: 'a + ToOwned + ToSql<ST, DB> + ?Sized, DB: Backend, Self: Debug,

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, DB>) -> Result

impl<DB> ToSql<Binary, DB> for Vec<u8>where DB: Backend, [u8]: ToSql<Binary, DB>,

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, DB>) -> Result

impl<DB> ToSql<Binary, DB> for [u8]where for<'a> DB: Backend<BindCollector<'a> = RawBytesBindCollector<DB>>,

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, DB>) -> Result

impl<DB> ToSql<Text, DB> for strwhere for<'a> DB: Backend<BindCollector<'a> = RawBytesBindCollector<DB>>,

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, DB>) -> Result

impl<DB> ToSql<Text, DB> for Stringwhere DB: Backend, str: ToSql<Text, DB>,

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, DB>) -> Result

impl<ST, T> ToSql<Array<ST>, Pg> for [T]where Pg: HasSqlType<ST>, T: ToSql<ST, Pg>,

Available on crate feature postgres_backend only.

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> Result

impl<ST, T> ToSql<Array<ST>, Pg> for Vec<T>where ST: 'static, [T]: ToSql<Array<ST>, Pg>, T: Debug,

Available on crate feature postgres_backend only.

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> Result

impl<ST, T> ToSql<Nullable<Array<ST>>, Pg> for [T]where [T]: ToSql<Array<ST>, Pg>, ST: 'static,

Available on crate feature postgres_backend only.

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> Result

impl<ST, T> ToSql<Nullable<Array<ST>>, Pg> for Vec<T>where ST: 'static, Vec<T>: ToSql<Array<ST>, Pg>,

Available on crate feature postgres_backend only.

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> Result

impl<ST, T> ToSql<Nullable<Range<ST>>, Pg> for (Bound<T>, Bound<T>)where ST: 'static, (Bound<T>, Bound<T>): ToSql<Range<ST>, Pg>,

Available on crate feature postgres_backend only.

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> Result

impl<ST, T> ToSql<Range<ST>, Pg> for (Bound<T>, Bound<T>)where T: ToSql<ST, Pg>,

Available on crate feature postgres_backend only.

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> Result

impl<T, ST, DB> ToSql<Nullable<ST>, DB> for Option<T>where T: ToSql<ST, DB>, DB: Backend, ST: SqlType<IsNull = NotNull>,

fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, DB>) -> Result

impl<__DB> ToSql<Nullable<BigInt>, __DB> for i64where __DB: Backend, Self: ToSql<BigInt, __DB>,

fn to_sql<'__b>(&'__b self, out: &mut Output<'__b, '_, __DB>) -> Result

impl<__DB> ToSql<Nullable<Binary>, __DB> for Vec<u8>where __DB: Backend, Self: ToSql<Binary, __DB>,

fn to_sql<'__b>(&'__b self, out: &mut Output<'__b, '_, __DB>) -> Result

impl<__DB> ToSql<Nullable<Binary>, __DB> for [u8]where __DB: Backend, Self: ToSql<Binary, __DB>,

fn to_sql<'__b>(&'__b self, out: &mut Output<'__b, '_, __DB>) -> Result

impl<__DB> ToSql<Nullable<Bool>, __DB> for boolwhere __DB: Backend, Self: ToSql<Bool, __DB>,

fn to_sql<'__b>(&'__b self, out: &mut Output<'__b, '_, __DB>) -> Result

impl<__DB> ToSql<Nullable<CChar>, __DB> for u8where __DB: Backend, Self: ToSql<CChar, __DB>,

fn to_sql<'__b>(&'__b self, out: &mut Output<'__b, '_, __DB>) -> Result

impl<__DB> ToSql<Nullable<Double>, __DB> for f64where __DB: Backend, Self: ToSql<Double, __DB>,

fn to_sql<'__b>(&'__b self, out: &mut Output<'__b, '_, __DB>) -> Result

impl<__DB> ToSql<Nullable<Float>, __DB> for f32where __DB: Backend, Self: ToSql<Float, __DB>,

fn to_sql<'__b>(&'__b self, out: &mut Output<'__b, '_, __DB>) -> Result

impl<__DB> ToSql<Nullable<Integer>, __DB> for i32where __DB: Backend, Self: ToSql<Integer, __DB>,

fn to_sql<'__b>(&'__b self, out: &mut Output<'__b, '_, __DB>) -> Result

impl<__DB> ToSql<Nullable<MacAddr>, __DB> for [u8; 6]where __DB: Backend, Self: ToSql<MacAddr, __DB>,

Available on crate feature postgres_backend only.

fn to_sql<'__b>(&'__b self, out: &mut Output<'__b, '_, __DB>) -> Result

impl<__DB> ToSql<Nullable<Oid>, __DB> for u32where __DB: Backend, Self: ToSql<Oid, __DB>,

fn to_sql<'__b>(&'__b self, out: &mut Output<'__b, '_, __DB>) -> Result

impl<__DB> ToSql<Nullable<SmallInt>, __DB> for i16where __DB: Backend, Self: ToSql<SmallInt, __DB>,

fn to_sql<'__b>(&'__b self, out: &mut Output<'__b, '_, __DB>) -> Result

impl<__DB> ToSql<Nullable<Text>, __DB> for strwhere __DB: Backend, Self: ToSql<Text, __DB>,

fn to_sql<'__b>(&'__b self, out: &mut Output<'__b, '_, __DB>) -> Result

impl<__DB> ToSql<Nullable<Text>, __DB> for Stringwhere __DB: Backend, Self: ToSql<Text, __DB>,

fn to_sql<'__b>(&'__b self, out: &mut Output<'__b, '_, __DB>) -> Result

impl<__DB> ToSql<Nullable<Timestamp>, __DB> for SystemTimewhere __DB: Backend, Self: ToSql<Timestamp, __DB>,

fn to_sql<'__b>(&'__b self, out: &mut Output<'__b, '_, __DB>) -> Result

Implementors

impl ToSql<Date, Pg> for PgDate

Available on crate feature postgres_backend only.

impl ToSql<Interval, Pg> for PgInterval

Available on crate feature postgres_backend only.

impl ToSql<Money, Pg> for PgMoney

Available on crate feature postgres_backend only.

impl ToSql<Numeric, Pg> for PgNumeric

Available on crate feature postgres_backend only.

impl ToSql<Time, Pg> for PgTime

Available on crate feature postgres_backend only.

impl ToSql<Timestamp, Pg> for PgTimestamp

Available on crate feature postgres_backend only.

impl ToSql<Timestamptz, Pg> for PgTimestamp

Available on crate feature postgres_backend only.

impl<'a, DB> ToSql<Text, DB> for MigrationVersion<'a>where Cow<'a, str>: ToSql<Text, DB>, DB: Backend,

impl<'a, __DB> ToSql<Nullable<Text>, __DB> for MigrationVersion<'a>where __DB: Backend, Self: ToSql<Text, __DB>,

impl<__DB> ToSql<Nullable<Date>, __DB> for PgDatewhere __DB: Backend, Self: ToSql<Date, __DB>,

Available on crate feature postgres_backend only.

impl<__DB> ToSql<Nullable<Interval>, __DB> for PgIntervalwhere __DB: Backend, Self: ToSql<Interval, __DB>,

Available on crate feature postgres_backend only.

impl<__DB> ToSql<Nullable<Money>, __DB> for PgMoneywhere __DB: Backend, Self: ToSql<Money, __DB>,

Available on crate feature postgres_backend only.

impl<__DB> ToSql<Nullable<Numeric>, __DB> for PgNumericwhere __DB: Backend, Self: ToSql<Numeric, __DB>,

Available on crate feature postgres_backend only.

impl<__DB> ToSql<Nullable<Time>, __DB> for PgTimewhere __DB: Backend, Self: ToSql<Time, __DB>,

Available on crate feature postgres_backend only.

impl<__DB> ToSql<Nullable<Timestamp>, __DB> for PgTimestampwhere __DB: Backend, Self: ToSql<Timestamp, __DB>,

Available on crate feature postgres_backend only.

impl<__DB> ToSql<Nullable<Timestamptz>, __DB> for PgTimestampwhere __DB: Backend, Self: ToSql<Timestamptz, __DB>,

Available on crate feature postgres_backend only.